Field of the Invention
The present disclosure relates to an image forming apparatus such as a copy machine, a multifunction peripheral, etc. In particular, the present disclosure relates to technology to replace a component which is replaceable in the image forming apparatus.
Description of the Related Art
Some image forming apparatuses comprise a photosensitive drum on which toner images are formed, and comprise an intermediate transfer belt to which toner images are transferred from the photosensitive drum. In a case where the toner images are transferred to the intermediate transfer belt from the photosensitive drum, a transfer roller is brought into pressure contact with the photosensitive drum through the intermediate transfer belt. It is often the case that the photosensitive drum or a unit including the photosensitive drum and the intermediate transfer belt or a unit including the intermediate transfer belt of the image forming apparatus of this kind are components which are individually and independently replaceable. In the following, the intermediate transfer belt or the unit including the intermediate transfer belt is referred to as “intermediate transfer belt unit”.
Some image forming apparatuses are capable of setting “color priority mode” and “monochrome priority mode” to reduce standby time at the time of image formation. When it is expected that color image formation is mainly used, “color priority mode” is set. In the color priority mode, the image forming apparatus brings all the photosensitive drums into contact with the intermediate transfer belt in a standby state. When it is expected that monochrome image formation is mainly used, “monochrome priority mode” is set. In the monochrome priority mode, the image forming apparatus brings only the black photosensitive drum into contact with the intermediate transfer belt in the standby state. A user can switch setting between the color priority mode and the monochrome priority mode.
In a case where replacement of the photosensitive drum or the intermediate transfer belt unit is carried out with the photosensitive drum brought into contact with the intermediate transfer belt, friction is caused therebetween. Due to this, deterioration is caused at parts where the photosensitive drum contacts with the intermediate transfer belt. Thereby, when replacement of the photosensitive drum or the intermediate transfer belt unit is carried out, the two of them need to be separated. The United States Patent Application Publication No. US2014/0169804 discloses a technology that at the time of replacing the photosensitive drum or the intermediate transfer belt, all the photosensitive drums are separated from the intermediate transfer belt in a standby mode.
In a case where the photosensitive drum is manually separated from the intermediate transfer belt, a mechanism for the manual separation is required. This increases the number of parts and the manufacturing cost. Further, in a case where the photosensitive drum is automatically separated from the intermediate transfer belt at the time of replacement, the photosensitive drum will be brought into contact with and separated from the intermediate transfer belt. Such operations will be performed every time the image formation is started and ended, which will be continued till the user carries out the replacement. Due to this, the image forming processing is time-consuming process. Also, due to unnecessary contact of the photosensitive drum with the intermediate transfer belt and unnecessary separation of the photosensitive drum from the intermediate transfer belt, noise is caused. Further, in a case where the photosensitive drum other than the black photosensitive drum reaches replacement timing in the monochrome priority mode, all the photosensitive drums are uniformly separated from the intermediate transfer belt. Thereby when performing next print job, unnecessary contacting operation occurs.
An image forming apparatus which can reduce any unnecessary mechanism or operation while allowing replacement of components which are replaceable, such as the photosensitive drum, the intermediate transfer belt, etc., is thus required.